Variable Area Fan Nozzle Actuation from Fixed Nacelle Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing VAFN actuation systems are heavy, complex, and difficult to maintain due to actuators being mounted on the translating sleeve, leading to increased drag, reduced fuel efficiency, and the need for cumbersome couplings.
Innovation Solution
A VAFN actuation system with fluid-power actuators mounted on the nacelle fixed structure, allowing for a lightweight, less complex design that includes a cylinder with axially aligned chambers and pistons, and a translating sleeve actuator to control the VAFN cowl position, using pneumatic or hydraulic fluid control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If actuators are mounted on the translating sleeve, then the VAFN can be actuated, but the system weight increases and drag increases
Solution Approach 1:
The actuator is extracted from the translating sleeve and mounted on the fixed structure instead. This removes the actuator weight from the moving assembly, reducing the weight that must be moved during thrust reverser operation, while still enabling VAFN actuation through the coupling mechanism.
Solution Approach 2:
A coupling mechanism serves as an intermediary between the fixed structure actuator and the translating sleeve VAFN. This intermediary transfers the actuation force without requiring the actuator to be directly mounted on the translating sleeve, solving the mounting problem while maintaining actuation capability.
2Ease of operation
If actuators are mounted on the translating sleeve, then the VAFN can be actuated, but the system complexity increases
Solution Approach 1:
By extracting the actuator from the translating sleeve and mounting it on the fixed structure, the complex coupling mechanisms required for actuator mounting on the translating sleeve are eliminated, reducing overall system complexity while maintaining actuation functionality.
3Ease of operation
If actuators are mounted on the translating sleeve, then the VAFN can be actuated, but fuel efficiency decreases
Solution Approach 1:
Removing the actuator from the translating sleeve reduces the weight of the moving assembly, which decreases the energy required to move components during thrust reverser operation, thereby improving fuel efficiency while maintaining VAFN actuation capability.
4Adaptability or versatility
If multiple components are used for actuation, then the VAFN can be controlled, but maintenance difficulty increases
Solution Approach 1:
By extracting the actuator from the translating sleeve and mounting it on the fixed structure, the actuator becomes a stationary component that is easier to access and maintain. This reduces maintenance difficulty while preserving the multi-component control capability needed for VAFN operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces weight, complexity, and maintenance requirements while improving fuel efficiency and reducing engine noise by decoupling the actuators from the translating sleeve, enabling precise control of the VAFN cowl position.
Implementation Method 1
fluid-power VAFN actuator configured to extend between a nacelle fixed structure and a VAFN cowl
Implementation Method 2
fluid-power actuator configured to extend between a nacelle fixed structure and a VAFN cowl
Data Source
AI summary
A variable area fan nozzle (VAFN) actuation system is disclosed. The VAFN actuation system is part of an aircraft nacelle, comprising a thrust reverser translating sleeve and a VAFN cowl. The system may translate the VAFN cowl to various positions to optimize engine performance. The system works in two phases. The first phase occurs when the translating sleeve is stowed. During this time, a linear, fluid-pressure VAFN actuator with multiple pistons may translate the VAFN cowl forward and aftward, and hold it in various fixed positions. The second phase occurs when the translating sleeve deploys and then stows. During this time, the actuator may allow the VAFN cowl to travel with the translating sleeve in a controlled manner. When the translating sleeve deploys, the VAFN cowl is pushed aftward by the translating sleeve. When the translating sleeve stows, the VAFN cowl is pulled forward with it.